Lay summary

The problem

Many decisions made by health services about which treatments to provide are informed by assessments of value for money. To do this requires a way of measuring the impact on the health of patients. Over the past decades, a very common way of doing this has been by using the EQ-5D-3L. This is a set of five questions (covering mobility, ability to self-care, ability to undertake usual activities, pain and discomfort, and anxiety and depression) that asks people whether they have no problems, some problems or severe problems. Five dimensions of health and three levels of responses for each dimension, hence EQ-5D-3L. Each set of responses can be given a score that has been calculated from surveys of the general population. A redesigned version (known as EQ-5D-5L) now exists, with improved wording of the questions and five levels of response (no difficulties; slight difficulties; moderate difficulties; severe difficulties; extreme difficulties).

Evidence to date

The evidence that exists to date on the suitability of EQ-5D in people with dementia comes from the EQ-5D-3L version. In this project, we assessed whether the enhanced version, EQ-5D-5L, is suitable for use with people with dementia. Some of the issues with using EQ-5D-5L are around the fact that people with dementia may have complications with cognition.

What did we do?

We conducted a systematic review of the literature. It is called a systematic review because it follows a rigorous method that can be reproduced by others to arrive at similar results. This method ensures that the findings are not biased. First, we searched the literature, identified 290 papers. We sifted these papers and agreed that only 20 were relevant to the research question. We reviewed the papers and pulled out data that were informative around the suitability of EQ-5D-5L. We presented the data in tables and explained what we found.

What did we find?

We found that EQ-5D-5L was overall suitable for use with people with dementia. However, we did not have much evidence on whether it can measure change over time.

As the condition worsens, people with dementia are unable to complete the questionnaire by themselves. In such instances, it is common practice for their friends, family members, carers and healthcare professionals to complete the questionnaires on their behalf. We found evidence that there are major differences in the way people with dementia rate their health and how others completing the questionnaire on their behalf do so.

Implication of this research

Currently there is no guidance on how to combine scores directly generated from people with dementia with scores when others complete the questionnaires on their behalf.